Do You Need a Refresher on Physics?
Are you curious about these questions:
How does a rainbow form? Is levitation possible? Do time machines exist? What does 'quantum' mean? What is the maximum force value found in nature? Is 'empty space' really empty? Is the universe a set? Which problems in physics are still unsolved?
A free online physics text book is available at this site. Chapter by chapter you can explore the solutions or some cases the lack of solutions, in an easy to understand text book.